1. Field of the Invention
The present invention relates to mines, and in particular, to accessories that can be secured to a mine in order to destroy it.
2. Description of Related Art
Land mines are still considered a necessary part of warfare. Of course, a lingering problem is finding, and disabling or destroying the land mines after hostilities cease. While combatants may try to make maps indicating locations of land mines, these maps are often hastily made and inaccurate, or are lost in the destruction that is part of armed conflict. Oftentimes, there is simply not the resources available to devote the time needed for carefully tracking down, and extracting or detonating these mines.
There have been many proposals for disabling or destroying land mines after they are no longer needed. These designs have employed internal timing devices or remote controls for either disabling or detonating the mine. These features, however, are part of the original land mine as manufactured. Existing inventories of land mines cannot be simply modified to include these safety features.
For example, in U.S. Pat. No. 3,603,258 pin 106 punctures diaphragm 104 after a mine is armed. The punctured diaphragm allows piston 96 to slowly move and eventually operate a mechanism to self-destructively detonate the mine. This mechanism is internal and cannot be readily used to retrofit a mine to achieve self-destruction. See also U.S. Pat. No. 3,739,725 (hydroscopic material 18 gradually softens to withdraw pin 13, which causes a mine to self-destruct).
In U.S. Pat. No. 6,142,080 an electronic timer senses the cessation of spinning of a projectile to start a timer that eventually will electrically detonate the explosive charge. In U.S. Pat. No. 3,657,571 an electronic timer is used to self-destruct a land mine. In U.S. Pat. No. 6,244,184 a timer is started upon the launch of a projectile carrying submunition grenades. Capacitors in the timing circuits in each of the grenades self-destruct the grenades after a period of time. None of these technologies are readily implemented as a retrofit. See also U.S. Pat. No. 3,983,819.
Encoded signals have been used to trigger underwater devices designed to destroy underwater mines. In U.S. Pat. No. 4,369,709 an underwater device is armed after reaching a proper operating depth. The device can be detonated by coded signals received through a hydrophone. In U.S. Pat. No. 5,042,387 a device has an upper buoyant portion and a lower sinking portion, which are both able to attach to a mooring line of a mine. The upper and lower units detach and move toward the mine and the mine seat, respectively. A sonar signal from a surface ship detonates both devices to destroy the mine and to sever the mooring line. See also U.S. Pat. Nos. 4,696,234; 4,970,957; 5,771,833; and 6,308,633. These references concern highly specialized underwater equipment and do not teach techniques for simply retrofitting land mines in order to safely destroy or disable them.
In U.S. Pat. No. 5,415,103 an interrogation unit can program a land mine to set the conditions under which the land mine will detonate. See column 1, lines 16-17. The electrical firing circuit of U.S. Pat. No. 5,218,574 provides several operating modes for a land mine. In one mode, an electrolytic timing device can detonate the land mine after a predetermined delay.
In U.S. Pat. No. 4,856,431 a directional mine is armed by inserting firing unit 6, which is locked into place by pin 15. The mine can be detonated by firing the igniter 11. After a pre-programmed amount of time, however, an electromagnet retracts pin 15 to eject unit 17, thereby disarming the mine. This reference is relatively complicated and does not lend itself to a simple retrofit.
In U.S. Pat. No. 4,712,478 slider 30 has a passage that moves into position just before detonation to create a firing path. The land mine can be neutralized by an undefined circuit that fires detonator 44 before slider 30 is in the armed position. Alternatively, the battery that operates circuit 10 can run down and disable the land mine. This reference has no teachings that would allow a simple retrofit for existing land mines.
In U.S. Pat. No. 4,854,239 a munition is fired by two explosively powered pistons, if they are fired in a proper sequence before a third piston is fired. Premature firing of the third piston will fracture a component, which is then elevated to indicate the munition is disabled. Again, this complicated reference would not be suitable for a simple retrofit.
See also U.S. Pat. Nos. 3,115,834; 3,447,461; 3,667,387; 4,058,061; 4,712,480; 4,854,239; 5,511,482; and 6,112,668, cited in the pending U.S. patent application Ser. No. 09/578,096, filed May 25, 2000 by the same inventor. See also U.S. Pat. Nos. 3,667,387 and 3,994,227.
Accordingly, there is a need for a self-destruct accessory that can be installed on a land mine in a simple and reliable fashion.
In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a self-destruct accessory for a mine whose case has a cap that can be depressed to detonate the mine. The accessory includes a cover sized to fit on the cap and has a plurality of lines for securing the cover to the mine. Also included is an explosive charge mounted upon the cover and a detonator located adjacent to the explosive charge. Firing of the detonator can cause the explosive charge to explode. The explosive charge can explosively depress the cap when the cover is mounted on the cap. The accessory also includes a remotely controllable device coupled to the detonator for firing it.
According to another aspect of the invention a method employing an explosive cover can destroy a mine whose case has a cap that can be depressed to detonate the mine. The method includes the step of fitting on the cap the explosive cover. The cover holds an explosive charge and a detonator. Another step is securing the cover to the mine with a plurality of lines. The method also includes the step of sending a detonation signal to the detonator from a remote location to detonate the explosive charge and explosively depress the cap in order to detonate and destroy the mine.
By employing the foregoing principles, an improved technique is achieved for destroying a mine with a self-destruct accessory. In one preferred embodiment, a cover is designed to fit closely over the cap of a land mine. Preferably, a number of straps extend from the edge of the cover and are used to secure the cover to the land mine. The ends of the straps can be fastened together using various connectors or buckles. Alternatively, the straps can extend from the side of the cover and attach to a fastener on the opposite side of the cover. In any event, the cover is installed in such a way that the land mine can be deployed in the usual fashion and will explode when pressure is applied to be cover to depress the cap of the land mine.
In a preferred embodiment an explosive charge can be mounted atop a supporting plate of the cover. When the land mine is no longer needed, an encoded signal can be sent to a remotely controlled detonator in the cover. This detonator can ignite a primer that in turn detonates the main explosive charge. The main explosive charge produces a pressure wave that depresses the cap of the land mine so it explodes safely.